Windows only: Universal Viewer, as its name implies, aims to be a universal file viewer capable of opening almost any file, without making you hunt down required programs for unusual file types.

Universal Viewer supports a wide variety of multimedia, image, and document formats (listed below). While it supports opening a truly vast array of file types, it doesn't support Microsoft Office documents unless Office is already installed. Other than that, most files are supported without any special work on your part. Universal Viewer also has a navigation panel, which allows for easier file navigation. It's not enabled by default, so you'll need to turn it on in the Interface tab in the configuration settings.

In addition to the file viewing, Universal Viewer also supports additional plug-ins and can convert nearly any document type to friendly old plain text.

Here's a list of formats the app supports out-of-the-box (see CyberNet's post for a more detailed breakdown of the over 200 supported file types):

The application integrates into Windows Explorer's context menu, so all you need to do is right-click a file and select "Universal Viewer." In addition, it can also be integrated into other popular file managers. Universal Viewer is a freeware application for Windows platforms only. Got a similar tool you use to fill this need, or do you just hunt down and install whatever apps need installing when you need them? Let's hear it in the comments.